Question

I am sure this is really, really simple but why does the following not work.

var o = function() { };
o.prototype.print = function( ) { console.log("hi") };
o.print(); // console message: Object function o() { } has no method 'print'

Fiddle here

UPDATE

Why does this also not work

var o = function() { };
o.prototype.print = function( ) { console.log("hi") };
var c = Object.create( o );
c.print();

I can start a new question if necessary.

Answer 1

1. Question

I am sure this is really, really simple but why does the following not work.

o is a constructor for new objects, you have to create a new object in order to use prototype methods:

var x = new o();
x.print();

2. Question

Why does this also not work

Because Object.create takes a prototype and not an object:

var o = function() { };
o.prototype.print = function( ) { console.log("hi") };
var c = Object.create( o.prototype );
c.print();

See also

• MDN: Inheritance and the prototype chain
• MDN: Object.create
• JSFiddle with the first example
• JSFiddle with the second example